For OS X, you might also consider Shift+Option+CMD+V, which pastes using the formatting of the target document. I have found this does not work for all target applications, however. (PowerPoint is one. Lame.)

If you find you always desire to paste without formatting, you can remap CMD+V in OS X:

  * Go to System Preferences > Keyboard > Keyboard Shortcuts > Application Shortcuts
  * Click the + under the right-hand list to add a shortcut
  * Application: All; Menu Title: Paste and Match Style; Keyboard Shortcut: type CMD+V

Ask MetaFilter's discussion of above: http://ask.metafilter.com/187733/OSX-How-to-copy-plaintext-a...